Sort Processes by Memory Usage

FreeBSD

ps aux -h | sort -rn -k 5,6
vmstat -m
ps aux -m | head | awk '{$5=int(100 * $5/1024/1024)/100"GB";}{ print;}'

*Use zfs-stats to check how much is zfs using from your memory

Linux

sudo ps -eo size,pid,user,command --sort -size | awk '{ hr=$1/1024 ; printf("%13.2f Mb ",hr) } { for ( x=4 ; x<=NF ; x++ ) { printf("%s ",$x) } print "" }'